Retractable column for medical service outlets



Oct. 26, 1965 H. L. MAY ETAL 3,213,877

RETRACTABLE COLUMN FOR MEDICAL SERVICE OUTLETS Filed July 18, 1962 3 Sheets-Sheet l 20 MN: (All IIIL" H3 4%- 8| INVENTORS HAROLD L. MAY WAYNE W. HAY

AGE

5 Sheets-Sheet 2 FIG. 6

INVENTORS HAROLD L. MAY

BYWAYNE W. HAY- 1965 H. I.. MAY ETAL RETRACTABLE COLUMN FOR MEDICAL SERVICE OUTLETS Filed July 18, 1962 FIG. 7

Oct. 26, 1965 M ETAL 3,213,877

RETRACTABLE COLUMN FOR MEDICAL SERVICE OUTLETS Filed July 18, 1962 3 Sheets-Sheet 3 62a 62C 62d 67 2 62b x l I United States Patent 3,213,877 RETRACTABLE COLUMN FOR MEDICAL SERVICE OUTLETS Harold L. May and Wayne W. Hay, Madison, Wis., as-

signors to Air Reduction Company, Incorporated, New

York, N.Y., a corporation of New York Filed July 18, 1962, Ser. No. 210,687 9 Claims. (Cl. 137355.16)

This invention relates to an improved ceiling column for gas and electric service connections in medical or surgical facilities such as operating rooms, delivery and recovery rooms and the like. More particularly, the invention concerns such an improved retractable ceiling column which is of sturdy and relatively rigid construction and which is, at the same time, adapted to make available medical service outlets in a retractable portion of the column that is easily adjustable to desired vertical positions.

The growing demands upon existing hospital facilities necessitate more eflicient and effective use of operating and recovery room facilities. Further, the burdens and pressures exerted on medical and surgical personnel and the complex surgical techniques that have been developed, and continue to be developed, necessitate that the medical equipment and the auxiliary components employed during surgery or immediately afterwards during the critical period of recovery be of the utmost reliability in operation and afford the maximum degree of safety. It has been recognized as highly advantageous in furnishing electrical and gas connections for medical equipment and the like to avoid the necessity of having such connections in the form of wiring or gas conduits that extend along the floor or in other ways possibly obstruct the movement of personnel. Accordingly, it has been considered desirable to provide suitable service outlet stations in conveniently located wall outlets or ceiling fixtures which may be arranged in close proximity to the operating table or site at which such services are needed for treatment of the patient.

Considerable difficulty has been encountered, however, in affording a completely satisfactory fixture for suspending gas and electrical service connections from a ceiling outlet due, in large part, to the inability to render such structures sufliciently rigid so as to avoid eventual damage or wear during continued use and to objectionable binding that is characteristic of such apparatus, which renders selective vertical adjustment of the mounting difficult and cumbersome.

Accordingly, it is an object of the present invention to provide a retractable ceiling outlet for medical service connections which is easily and freely adjustable to desired vertical positions and which alfords a high degree of structural rigidity and reliability of operation for such purposes.

It is also an object of the present invention to provide such a ceiling column for medical service connections characterized by compactness, freedom from troublesome maintenance and care, and simplicity of construction.

These and other objects and advantages of the present invention may more readily be understood by reference to the following description of a preferred embodiment of the invention and the accompanying drawings, in which:

FIG. 1 is a perspective view illustrating the exterior of a retractable ceiling column in accordance with the invention;

FIG. 2 is a vertical elevation view, partially sectioned, of the retractable column illustrated in FIG. 1;

FIG. 3 is a vertical elevation partially in section of the retractable column as viewed from the left-hand side of the column as seen in FIG. 2;

FIG. 4 is a horizontal sectional view taken along the line 44 in FIG. 2 in the direction of the arrows;

FIG. 5 is a sectional view along the line 55 in FIG. 4 looking in the direction of the arrows;

FIG. 6 is a partial sectional view showing the compensating spring mounting taken along the line 6-6 in FIG. 4 looking in the direction of the arrows;

FIG. 7 is a partial sectional view of the lower housing locking mechanism taken along the line 77 in FIG. 6 looking in the direction of the arrows; and

FIG. 8 is a partial sectional view taken along the line 8-8 in FIG. 4.

Referring to the drawings, a retractable ceiling col umn is shown at 10 in FIG. 1, which is suspended from the ceiling C such as in an operating room, recovery room or the like, in close proximity to the point at which the various services provided by the column outlet may be used. Depending upon the particular requirements at the location of the outlet, various service connections may be furnished therein. A typical service connection, for example, may include gas outlets such as for oxygen, nitrous oxide and air, a vacuum outlet, and electrical service connections such as a conventional volt outlet or for electric equipment such as EEG and EKG instruments. The specific receptacles for these connections may, of course, be provided in various convenient ways in the column, the receptacles being indicated generally at 12 and 14 at the lower end of the retractable lower housing 16 of the column which is telescopically received in an upper housing 18 thereof. The column is shown in FIG. 1 in its uppermost position in which the connections 12 and 14 remain exposed for use. The lower portion of the column, however, may be extended to progressively lower positions as indicated by the dotted line 18. In each of the selected lower positions, all of the outlet connections remain immediately available for use.

It will be understood that the connections or receptacles shown at 12 and 14 are conventional gas and electrical connections for medical use. A typical quick disconnect type of gas outlet is shown, for example, in US. Patent No. 2,905,487. The gas outlets preferably also are the so-called noninterchangeable type which prevent the connection inadvertently of a hose or conduit with any gas other than that for which it is specifically intended. Desirably, all the gas and electrical outlets are identified by means of color coded plates in a manner which is conventional in practice.

The construction of the column may be more readily understood by reference to FIG. 2. The upper column is comprised of four vertically depending rack bars 20 threadedly secured at their upper ends by suitable nuts 22 in a horizontal mounting plate 24. The plate 24 is, in turn, suitably anchored in framework or other base support within the ceiling C such as by means of the lugs 25 which may, for example, be bolted to depending lugs 25' of a suitable fixture plate 26 mounted in the ceiling. A skirt 27 removably secured around the upper end of the column encloses the exposed ends of the bolts holding the mounting plate 24 in place and covers the rough opening in the ceiling. A gas connector fitting is shown at 28 and electrical couplings shown at 30 which are secured in the plate 24. It will be understood that the necessary supply conduits of gas and electricity are brought to the location at which the column is mounted where appropriate connections may be made to the upper ends of the receptacles 28 and 30 as is well understood in the art.

The lower housing 16 of the column is comprised of a carriage member 32 that is slidably mounted on the vertically extending rack bars 20 as will hereinafter be more fully described. A cylindrically shaped wall panel secured at its upper end to the sides of the carriage frame 32 depends downwardly thereform and supports at its lower end a bottom closure plate 36. The carriage side panel and bottom plate, thus, cooperate to form a relatively rigid cylindrical housing which is vertically adjustable on the rack bars 20. An inconspicuous but easily removable access panel is provided on one side of the side panel 34, such for example as shown by the panel 34' in FIG. 4, secured at its upper end by a clip 35, FIGS. 2 and 4, and at the lower end by a clip such as 35 in FIG. 2. This access panel can be slipped out for periodic inspection of the interior of the column.

At its lowermost extended position, the movement of the lower housing 16 is restricted by the limit pins shown at 38 fixed at the lower ends of the rack bars so as to engage the bottom of the carriage 32 at its extreme lower limit of travel. The lower housing 16 is capable of being raised by riding along the rack bars until the lower ends of the rack bars abut the bottom plate 36 of the lower housing. A shroud shown at 40, secured by screws 40 to the lugs of the ceiling fixture plate, forms an outer shield enclosing the rectangular frame formed by the rack bars 20 of the upper housing and is adapted to telescopically receive the lower housing as it is raised and lowered on the rack bars 20. A felt spacer pad 42 is carried at the lower end of the shroud and firmly compressed within the space between the lower end of the shroud and the cylindrical side walls of the side panels 34 of the lower housing. The felt pad 42 forms a sliding bearing which retards the passage of dust and the like upwardly into the shroud and also afrords assistance in increasing the rigidity of the column against side sway, particularly in the raised position of the lower housing.

Typical gas outlet connectors are shown at 28' mounted on supporting brackets 36' of the bottom panel 36 of the lower housing which are, for convenience, manifolded together and connected to a common hose connection 46 which is secured to the gas fitting 28. A typical electrical receptacle also is shown mounted on the bottom panel 36 which is electrically connected by the conductor 48 with the connector 30 at the upper end of the column. The outlet connectors and receptacles 28' and 30' are merely shown by way of illustration, it being understood that there may, of course, be several additional such outlet connections. In addition, one or more of the receptacles may be provided in the lower exposed portion of the side panels of the lower housing such as at 14 in FIG. 1. In order to accommodate the retraction and extension of the lower housing, each of the connecting hoses and electrical conductors, such as those shown at 46 and 48, are looped as at 46' and 48' to provide a suflicient excess length for extension of the lower housing. To accommodate the extension loops of the conductors and hoses and to avoid their entanglement during movement of the lower housing, a hanger plate, such as shown at 50 in FIG. 8, is mounted in the carriage 32 of the lower housing over which the hoses and conductors such as that shown at 46 may be looped and secured with a clip such as that at 52. The hanger plate 50 is conveniently constructed of sheet metal to form a curved portion and opposite ends such as at 53 bent at right angles which may be conveniently secured to the sides of the carriage 32 such as by screws 54. The mounting of the hanger plate 50 in the carriage 32 is further shown in FIG. 4 of the drawings in which the manner in which a series of additional hoses and conductors may be accommodated therein is also illustrated.

The lower housing carriage 32 is a rigid rectangular frame made up of four side plate members 60, 62, 64

and 66 which may be conveniently fastened together such as by means of the screws 67 at the adjacent corners. A set of meshed gears 62a, 62b, 62c and 62d are rotatably carried in the side plate 62 and a corresponding set of meshed gears 66a, 66b, 66c and 66d are rotatably supported in the side plate 66. Spacer panels 62' and 66 are secured in spaced confronting relation to the side plate members 62 and 66 respectively such as by the countersunk screws 68, seen in FIG. 2. The retaining screws carry spacer bushings, only the ends of which are seen at 68' in FIG. 5 in the drawings, which maintain the desired spacing between the spacer panels and the carriage side members. The spacer plates may be removed for replacement of any of the gears and when in place act as a retainer for maintaining the gears in alignment. The gears designated b, c and d of the respective gear trains are rotatably mounted on studs clamped axially between the sections of the side plates 62 and 66. The gears 62a and 66a are mounted on a common shaft 70 on which each of the gears is rigidly fastened such as by the keys 72 and 74, in order that rotation of either of the gear trains will impart equal rotation to the other as will hereinafter be more fully described.

The end gears 62a, 62d and 66a, 66d, of the respective gear trains, are in mesh with the teeth 20 of the adjacent corresponding rack bars 20. The side panels 60, 62, 64 and 66 of the lower housing carriage are so arranged in cooperation with the respective gears carried therein and the spacer panels 62' and 66 that a way is formed at each corner of the carriage in which each of the corrseponding ones of the vertical rack bars 20 is accommodated for vertical movement. The way for each of the rack bars and the engagement of the rack bars with the corresponding ones of the gears as well as the interengagement of the respective gears is preferably of relatively close tolerance in order to enhance the desired effect of facilitating movement of the carriage and strengthening the frame structure of the upper housing afforded by the carriage and gear members carried there- It may be seen that the respective gear trains contain 'an even number of gears so that the end gears of each of the trains rotate in the opposite direction and are, thus, disposed to impart equal forces in the same direction against their corresponding engaging rack bars, By warrant of the construction described, no matter what the distribution of loading on the column or the direct-ion in which force is applied to the lower column for adjusting its height, the respective .gear trains cooperate to distribute the load exerted on the upper housing and to cause the carriage to move upwardly or downwardly uniformly without binding. The end gears of each of the .gear trains are, of course, provided with an equal number of gear teeth and are so interconnected such as by the intermediate idler gears 62b, 62c and 66b and 660 as to rotate in equal increments. The idler gears are conveniently of substantially the same diameter and number of teeth as the end gears of the gear trains but, of course, these gears could be of a different size.

The vertical adjustment of the lower housing 16 is facilitated by a pair of compensating springs '80 and 81. These springs are of the negator type characterized by providing a substantially constant tensile force over the entire extent of movement of the lower housing to which the lower ends of the springs are connected. The negator springs are wound on a spool 82 seen in FIG. 4 which is freely rotatable on the shaft 70. It will be understood that the inner ends of the negator springs are fastened to the spool in the conventional manner. The upper ends of the negator springs are fastened by suitable screws to a bracket '84 depending from the mounting plate 24 of the upper housing. As a downward force is applied to the lower housing, the neg-ator springs and 81 unwind on the spool 82. When an upward force is applied, the Springs rewind themselves on the spool. The total upward force exerted by the springs is desirably such as to exceed by a slight amount the total weight of the lower housing and any equipment including connecting hoses and the like that may be mounted thereon during use. Accordingly, only a slight downward exertion on the lower housing is necessary to extend the column and, conversely, the lower housing may be readily raised without the necessity of overcoming the weight thereof. A shield 86 is secured in the carriage and extends partially around the spool 8 2 on which the negator springs are coiled soas to avoid any friction of the hoses and conductors against the spring during extension and retraction of the column. In order to accommodate the passage of the negator springs, the side panel 64 of the carriage 32 extending alongside lot the spool is advantageously cut away at 64 to provide a convenient opening through which the springs may he passed upwardly for attachment to the anchoring plate 84 as seen in FIG. 3. In order to compensate for the cut away portion of the side plate 64, a rod 88 extends between the side plates 62 and 66 of the carriage as seen in FIG. 7 to furnish additional strengthening tor the carriage tralme.

The lower housing 16 is rigidly locked at selected spaced vertical positions with respect to the upper housing by means of a locking rod 90 mounted in the carriage '32 as shown in FIG. 7. The rod 90, mounted for lateral displacement in suitable cavities 90 in the confronting side panels 6 2 and 66 of the carriage, is stepped at one end to form a reduced diameter pin '92 which is adapted to be inserted in any one of the selected vertically spaced locking .cavit-ies 94 of rack bar 20. A spring 96 is carried on the rod and adjusted to produce a desired torce urging the rod toward the right hy means of an adjustable stop 98, the spring being compressed between the stop and the adjacent side panel 62 [of the carriage. A locking handle 100, seen in FIG. 3, protrudes through the hottom closure plate 36 of the lower housing and is operatively associated with a vertically elongated anm :102 for actuating the locking rod 90. The arm 1102 is pivotally mounted at 103 in a supporting bracket 104 fastened at the underside of the side plate 64 of the lower housing carriage. At its upper end, the arm 4102 has a cam surface 106 arranged to bear against an adjustable collar 108 secured at a predetermined position along the rod 90. Movement of the lower end of the handle 1100 toward the right, as seen in FIG. 3, displaces the rod 90 toward the left retracting the locking pin 92 from its engaging position with the locking cavities of the rack bar 20 seen in FIG. 7. With the handle in this position, the carriage and lower housing assembly of the column may be vertically adjusted to a preselected position. After the carriage has been positioned, the handle is moved toward the left and a suitable insertion made of the locking pin 92 with one of the locking cavities 94 locking the carriage. A spring 110 is stretched between the bottom of the carriage 3'2 and the handle :2 heloW its pivot point so as to normally urge the control handle toward inoperative position and allow the spring 96 to urge the bar 90 toward the right to maintain locking engagement.

In conventional sliding pedestal devices in which a member is adapted to be extended or retracted on a sliding support structure, a lateral rigidity must normally be imparted by a sufiicien't longitudinal extent of the slide hearing. Frequently, such a bearing member must be augmented with additional strengthening structure to impart a sufficient lateral stability to prevent binding of the sliding member or to afford rigidity against lateral motion where the pedestal or similar supporting member is of a cantilever type construction. The present retractable assembly, however, is not dependent upon elongation of its bearing member for avoidance of binding and enhancement of lateral stability. Thus, for example, the vertical extent of the way in which each of the vertical rack bars is received in the vertically movable carriage 32 of the column is not relied upon as the primary means for avoiding binding of the carriage or lateral rigidity of the upper framework suspension of the column. This is of considera'ble advantage in apparatus of the present type wherein elongation of the bearing surfaces of the carriage in such a manner would necessitate the reservation of an additional vertical length of the slide bars on which engagement of the gears.

6 the carriage would move which would reduce the over-all height of vertical adjustment afforded :for a given length of the column. In accordance with the present construction, the vertical dimension of the carriage in which the rack bars are received may be elfectively minimized without detracting from the smooth operation and lateral rigidity of the column by the cooperative action of the engagement of the gear trains in the carriage. Referring, "for example, to FIG. 5 of the drawing, it may be seen that as the carriage 3'2 is urged upwardly the gear 62a will be caused to rotate in a counterclockwise direction. C-orresponding thereto, the gear 62d actuated through the idler gears 62b and 62c will also he caused to rotate in a clockwise direction and in so doing will necessarily ride upwardly along the teeth of the rack bar 20 with which it is in engagement. By Warrant of the interconnection of the gear trains 62a-d and r66a-d through the interlocking shaft 70, the same driving force will be exerted at each of the corners of the carriage and each corner of the carriage must necessarily rnove upwardly at the same rate. Such action, it will be seen, is not dependent upon the elongation of the hearing surface of the ways through which the rack bars translate, although, of course, these ways must cooperate with the gears in order to maintain a proper engagement hetween the gears and the teeth of the rack bars.

The effect of the meshed gears upon the rigidity of the frame of the upper housing may be visualized also by reference to FIG. 5. When the carriage is locked in a given vertical position by engagement of the locking rod as before described, it can be seen that lateral force applied against any side of the column will create a distribution of forces tending to cant the carriage with respect to the supporting rack bars 20. Such relative displacement of the carriage, however, is directly resisted by the action of the engagement of the gears since it will be seen, for example, that the gears engaged with each of the rack bars are inherently constrained to rotate in unison and in the proper direction. Thus, any exertion tending to cant the carriage 32 would tend to urge end gears of the respective gear trains to rotate in directions which are in direct opposition to the restraint afforded by the Consequently, any such lateral forces applied to the column are restrained by the gears and lateral movement effectively resisted without the necessity of providing any substantial elongation of the sliding bearings of the ways in the carriage in which the rack bars are received.

In operation, it will be understood that the ceiling column, when not actually in use, will normally be in its uppermost retractable position, shown in FIG. 1. The various accessory equipment, such as vacuum trap bottles, vacuum regulators, pressure manometers and the like may conveniently be mounted at the appropritae gas outlet connection at the lower end of the lower housing in readiness for use as will be well understood to those skilled in the art. Hooks H on the lower end of the column may be used to support intravenous bottles or the like. When it is desired to place the column in use, the handle may be grasped, displaced sideways to retract the locking rod as above described and the lower column extended to a desired lower level and the handle then released to permit the locking rod to engage and secure the lower column in a fixed position. Appropriate electrical conductors may then be plugged into the receptacles at the bottom of the lower housing and gas hoses connected from the appropriate treatment apparatus to the corresponding outlets mounted at the lower housing of the column. Such gas hoses and conductors depending in this manner from the bottom of the ceiling column can be efiectively kept out of the way of the path of move ment of medical personnel and obstruction with the service connection thus minimized. It will be apparent from the foregoing description of the described embodiment of the invention that the extendable column is capable of smooth and easy operation and that the column will effectively withstand the lateral or eccentric forces applied thereto even though the structure is of an extremely compact nature and relatively light in weight.

It will be understood, however, that various modifications may be made in the embodiment herein shown and described without departure from the invention as defined in the following claims.

We claim:

1. A retractable ceiling column for service outlets comprising an upper fixed housing having laterally spaced vertically suspended rack bars therein fixed at their upper ends and unsecured at their lower ends, a lower housing slidably mounted on said vertically extending rack bars manually movable vertically thereon, having ways in which said rack bars are embraceably and slidably received, a gear train carried in such lower housing in operative engagement with each of said rack bars to form a gear drive therebetween, means for selectively locking said lower housing with said rack bars in a plurality of spaced vertical positions and service receptacles carried on said lower housing for detachably receiving connections for said services.

2. A retractable ceiling column for service outlets in accordance with claim 1, wherein supply connection for said services are fixedly mounted in said upper housing and extensible conduit means extend between said supply connections in said upper housing and said service receptacles carried on said lower housing for maintaining said supply connections and said receptacles in communication in each of said vertically spaced positions of said lower housing.

3. A retractable ceiling column for service outlets in accordance with claim 1, wherein a substantially constant force spring is operatively secured between said upper housing and said lower housing to effectively counterbalance the weight of said lower housing.

4. A retractable ceiling column for medical service outlets comprising an upper fixed housing, a lower vertically movable housing arranged to betelescopically received in said upper housing, four vertically suspended rack bars secured at their upper ends and unsecured at their lower ends in said upper housing and forming a downwardly depending parallelepiped frame structure, a carriage forming a part of said lower housing having ways embraceably and slidably receiving said rack bars, said carriage being manually movable vertically on said rack bars, gears mounted in said carriage in operative engagement with each of said rack bars, means forming a reversible drive connection between each of said gears for rotating said gears in unison during vertical displacement of said carriage on said rack bars, means forming a fixed engagement between said carriage and said rack bars for selectively locking said carriage at selected vertical spaced positions on said rack bars, and service receptacles carried on said lower housing for detachably receiving connections for said services.

5. A retractable ceiling column in accordance with claim 4, wherein said lower housing includes side panels forming a rectangular cylindrical shell depending from said carriage and receiving said vertical rack bars therein during upward vertical movement of said carriage, said service receptacles being mounted substantially at the lower extremity of said cylindrical shell, fixed medical service outlet means disposed within said upper fixed 6. A retractable ceiling column for medical service outlets in accordance with claim 4, wherein a series of meshed gears forming a gear train provides an operative drive connection between one pair of said vertically extending rack bars and a second series of meshed gears forming a second gear train provides an operative drive connection between the other pair of said vertically extending rack bars and wherein a corresponding gear of each of said trains is linked to rotate in unison.

7. A retractable ceiling column for medical service outlets in accordance with claim 6 wherein said corresponding gears of said respective gear trains linked together for rotation in unison are mounted on a common shaft and wherein said shaft carries a rotatable spool on which is mounted a coiled spring, the free end of which is secured to said upper housing to impart a substantially constant force tending to raise said lower housing.

8. A retractable ceiling column for medical service receptacles comprising an upper housing having an upper vertically extending rectangular cylindrical shell rigidly secured at its upper end and open at its lower end, four vertically suspended rack bars within said upper shell secured at their upper ends and free at the lower ends thereof, said rack bars being substantially parallel and spaced to form a generally parallelepiped, freely-suspended frame within said shell, a lower substantially rectangular cylindrical shell having a carriage member secured in its upper open end, said carriage member having ways therein embraceably and slidably receiving said rack bars, said lower shell and carriage being adapted to be displaced vertically such that said rack bars telescope within said lower shell and said lower shell being arranged to telescope within said upper shell, gear train means carried within said carriage member in engagement with each of said rack bars forming a driving connection between each of said rack bars, medical service receptacles carried at substantially the lower, nonreceding extremity of said lower cylindrical shell, extensible means connecting said receptacles with fixed service connections in said upper housing, locking means effective to form a fixed, releaseable engagement between said carriage and at least one of said rack bars in selected vertically spaced positions of said carriage and slide bearing means mounted within the open end of said upper cylindrical shell acting against the telescoping sides of said lower shell.

9. A retractable ceiling column according to claim 8, wherein said locking means comprises a locking element mounted in said carriage having a vertically extending actuating arm operatively extending downwardly in said lower shell and projecting from the bottom thereof, said locking element being arranged to be selectively displaced to form a locking engagement between said carriage and at least one of said rack bars.

References Cited by the Examiner UNITED STATES PATENTS 300,493 6/84 Merichenski 248334 612,780 10/98 Mansione 74-422 1,634,854 7/27 Scollard 18719 2,181,399 11/37 Forbes 312247 2,876,362 3/59 Foderaro 248334 X 3,032,057 5/62 Mays 312247 X RICHARD W. COOKE, JR. Primary Examiner.

JACOB L. NACKENOFF, Examiner. 

1. A RECTRACTABLE CEILING COLUMN FOR SERVICE OUTLETS COMPRISING AN UPPER FIXED HOUSING HAVING LATERALLY SPACED VERTICALLY SUSPENDED RACK BARS THEREIN FIXED AT THEIR UPPER ENDS AND UNSURECED AT THEIR LOWER ENDS, A LOWER HOUSING SLIDABLY MOUNTED ON SAID VERTICALLY EXTENDING RACK BARS MANUALLY MOVABLE VERTICALLY THEREON, HAVING WAYS IN WHICH SAID RACK BARS ARE EMBRACEABLY AND SLIDABLY RECEIVED, A GEAR TRAIN CARRIED IN SUCH LOWER HOUSING IN OPERATIVE ENGAGEMENT WITH EACH OF SAID RACK BARS TO FORM A GEAR DRIVE THEREBETWEEN, MEANS FOR SELECTIVELY LOCKING SAID LOWER HOUSING WITH SAID RACK BARS IN A PLURALITY OF SPACED VERTICAL POSITIONS AND SERVICE RECEPTACLES CARRIED ON SAID LOWER HOUSING FOR DETACHABLY RECEIVING CONNECTIONS FOR SAID SERVICES. 